Induction of chymotrypsinogen by hydrocortisone in embryonic chick pancreas in vitro

Hydrocortisone stimulated the accumulation of chymotrypsinogen by pancreas explants removed from 9-15 day old chick embryos and cultured in vitro in a chemically defined medium for 1 to 3 days. Most of the chymotrypsinogen produced by the explants was released into the medium during culture. Radioimmunoprecipitation studies show that hydrocortisone acts by accelerating the de novo synthesis of chymotrypsinogen. There was a lag of 10 to 15 hr in the response of the pancreas explants to hydrocortisone. When hydrocortisone was removed by washing 3 hr after the start of induction the same degree of induction was observed after incubation for 48 hr as when the hormone was present continuously. D actinomycin, added at the same time as hydrocortisone, inhibited the induction of chymotrypsinogen but when added 10 hr after the hormone it no longer inhibited induction.